Design a three layer flexible pavement system using the CBR method, knowing hat the present AADT is (6500 v/d) the heavy vehicles represent 25% of it. The ighway lifetime and the construction period about 18 years and the growth rate s (r30.02). The CBR values are as foll ows: Subgrade soil = 6%, sub-base = 7%, Base = 75%. %3D %3D

Design a three layer flexible pavement system using the CBR method, knowing hat the present AADT is (6500 v/d) the heavy vehicles represent 25% of it. The ighway lifetime and the construction period about 18 years and the growth rate s (r30.02). The CBR values are as foll ows: Subgrade soil = 6%, sub-base = 7%, Base = 75%. %3D %3D

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter20: Design Of Rigid Pavements

Section: Chapter Questions

Problem 22P

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Design a flexible pavement (Two way-Two lane) for a subgrade CBR value of 3.5,the number of daily traffic as shown in the table below, the reliability value is 90%, the standard deviation 0.35, the initial serviceability 4.5, terminal serviceability 2.20 and effect of weather swelling only. Assuming a 20-year design life and growth rate 2%. Assume that 80% of the ESALs in one direction.. (E2-30,000 psi, E3-11,000 psi, m. m, 1.08). Sketch cross section in your design. All axles should be taken in ESAL calculations. (Take IMPa =145.0 psi) Vehicle Class Passenger Car Single-unit truck Single-unit truck Semi-trailer Light truck Large semi-trailer Axles Weights 2 single axles, 2000 lb/axle 1 single axle, 8000 lb/axle 1 single axle, 14,000 lb/axle I single axle, 7000 lb/axle 1 tandem axle, 20,000 lb/axle I tredom axle, 28,000 lb/ axle 1 single axle, 12,000 lb/axle 2 tandem axles, 22,000 lb/axle 2 single axles, 3000 lb/axle 1 single axle, 12,000 lb/axle 2 tandem axles, 28,000 lb/axle Number…
A rigid pavement is designed with a 11-inch slab, an E_c of 6 million Ib/in^2, a concrete modulus of rupture of 432 Ib/in^2, a load transfer coefficient of 3.0, an initial PSI of 4.50, and a TSI of 2.5. The overall standard deviation is 0.56, the modulus of subgrade reaction is 190 Ib/in^3, and a reliability of 90% is used along with a drainage coefficient of 0.87. The pavement is designed assuming that traffic is composed entirely of trucks (50 per day). Each truck has one 20-kip single axle and one 42-kip tandem axle (the effect of all other vehicles is ignored). A section of this road is to be replaced (due to different subgrade characteristics) with a flexible pavement having a SN of 5 and is expected to last the same number of years as the rigid pavement. What is the assumed soil resilient modulus? (Assume that all other factors are the same as for the rigid pavement). Please report your answer as a decimal in units of Ib/in^2. For example, report 3000.6 Ib/in^2 as 3000.6.
Problem 1: A flexible pavement section is designed using a CBR of 20 for the subgrade. During construction it is found that the subgrade is softer with a CBR of 7. The contractor proposes to place a layer of select fill on top of the subgrade to compensate for this condition. How thick should the select fill layer be if the original pavement section is 8 inches HMA over 12 inches crushed aggregate base over subgrade. Assume a resilient modulus of 15,000 psi for the select fill and clearly describe the design method used to solve this problem as well as any assumptions and results PROBLEM 2: Design a rigid pavement that will last as long as the flexible structure from problem 1
B. A rigid pavement with a 10-inch slab thickness, 90 percent reliability, E. = 4 million lb/in², 600 lb/in² modulus of rupture, 150 lb/in³ modulus of subgrade reaction, a 2.8 load transfer coefficient, initial PSI of 4.8, final PSI of 2.5, overall standard deviation of 0.35, and a drainage coefficient of 0.8 is designed. The pavement's design life is 20 years. The three-lane road is built for vehicles with one 20,000-pound single axle, one 26,000-pound tandem axle, and one 34,000-pound triple axle. Calculate the projected daily truck traffic on the three lanes.
A rigid pavement is designed with a 10-inch slab,an Ec of 6 million lb/in^2, a concrete modulus of rupture of 432 lb/in^2, a load transfer coefficient of 3.0, an initial PSI of 4.7, and a terminal serviceability index of 2.5.The overall standard deviation is 0.35, the modulus of subgrade reaction is 190 lb/in^3, and a reliability of 90%is used along with a drainage coefficient of 0.8. The pavement is designed assuming traffic is composed entirely of trucks (100 per day). Each truck has one 20-kip single axle and one 42-kip tandem axle (the effect of all other vehicles is ignored). A section of this road is to be replaced (due to different subgrade characteristics)with a flexible pavement having a structural number of 4 and is expected to last the same number of years as the rigid pavement. What is the assumed soil resilient modulus? (Assume all other factors are the same as for the rigid pavement.)
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Pavement Design and Analysis - Design a HMA pavement structure for a 6-lane divided urban highway using the AASHTO method to accommodate the traffic loads and conditions as follows. Give two alternative layer thickness combinations.
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A flexible pavement is to be designed to last 10 years. The initial PSI is 4.2 and the TSI (the final PSI) is determined to be 2.5. The subgrade has a soil resilient modulus of 15,000 lb/in². Reliability is 95% with an overall standard deviation of 0.35. For design, the daily car, pickup truck and light van traffic is 40,000 and the daily truck traffic consists of 1500 passes of single-unit trucks with two single axles and 325 passes of tractor semi-trailer trucks with single, tandem, and triple axles. The axle weights are: Cars, pickups, light vans = two 2 kip single axles Single-unit truck = 8 kip single axle and 24 kip single axle Tractor semi-trailer truck = 10 kip single axle, 18 kip tandem axle, and 42 kip triple axle. ● ● M₂ and M3 are equal to 1 for the materials in the pavement structure. Four inches of hot- mix asphalt (HMA) is to be used as the wearing surface and 10 inches of crushed stone as the subbase. Determine the thickness required for the base if soil cement is the…
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